This was a really fascinating read, but subs/maritime topics fascinate me in general.
The sub in question is 200ft long. Has only been seen by accident due to TopGear Moscow photoshoot that happened to capture it surfaced off the coast in the background.
The sub docks underneath a mother ship sub which allows it to be transported.
The sub can go deeper than any US sub due to a weird construction style of titanium vessels inside the hull.
All of this happened in relatively shallow waters while being docked to the parent sub (something that wasn't revealed until later in the story)
